This invention relates to a cylinder band used to immobilize an air cylinder on a backplate of a buoyancy regulator for diving.
Cylinder bands used to immobilize an air cylinder on a backplate of a buoyancy regulator is well known. An example of such a cylinder band is disclosed in Japanese Unexamined Patent Application Publication No. 2002-240784 (REFERENCE). FIG. 7 of the accompanying drawings is a rear view showing the buoyancy regulator 101 disclosed in REFERENCE. For this buoyancy regulator 101, a cylinder band 102 is used. FIG. 8 is a sectional view of a belt 131 and a buckle 132 to illustrate procedures for use of the cylinder band 102. Referring to FIG. 7, the buoyancy regulator 101 comprises a jacket 103 adapted to be fed with air for buoyancy regulation, the cylinder band 102 and the backplate (not shown). An air cylinder 105 indicated by an imaginary line is immobilized on the backplate using the cylinder band 102. The air cylinder 105 is provided on its top with a first stage 108 from which a regulation hose 109 extends to a second stage (not shown). An inflation hose 112 extends to the dorsal side of the jacket 103. The cylinder band 102 comprises a belt 131 and a buckle 132 wherein the belt 131 extends through the dorsal side of the jacket 103 from the outer side to the inner side and again to the outer side and the buckle 132 allows the belt 131 to be length-adjusted.
In the case of the cylinder band 102 shown in FIG. 8, the belt 131 and the buckle 132 are coupled to each other with interposition of a coupler 135. A free end 134 of the belt 131 wound around the air cylinder 105 is guided successively in directions indicated by arrows P, Q, R and successively through a second insertion slit B and a third insertion slit C of the buckle 132 so that the air cylinder 105 may be somewhat tightened. From this state, the free end held with, for example, the left hand is lightly tugged to the left to strain the belt 131, on one hand, and a second end 172 guided through the slits of the buckle 132 held with the right hand is swung around a pivot 140 formed through the buckle 132 in a direction indicated by an arrow X, on the other hand. Consequentially, a region on an end surface 151 of a first end 171 in which the end surface 151 comes in contact with a peripheral surface 105a of the air cylinder 105 transfers from a region M1 to a region M2 and then to a region M3 whereupon the buckle 132 rises on the peripheral surface 105a as indicated by imaginary lines. Distances L1, L2, L3 from a center of A pivot 140 is fitted into a through-hole 152 formed through the first end 171. Distances from a center of the through-hole 152 to the respective regions M1, M2, M3 are represented by L1, L2, L3, respectively. The distance L2 as well as the distance L3 is larger than the distance L1. Such end surface 151 defines a cam surface serving to enhance a tensity of the belt 131 having been guided through the insertion slits B, C as the second end 172 swings. However, the buckle 132 rising on the peripheral surface 105a as indicated by the imaginary lines is in unstable state since the region M3 including the vicinity thereof in which the buckle 132 is in contact with the peripheral surface 105 presents a surface segment which is convexly curved toward the peripheral surface 105a or a flat surface segment. To keep the buckle 132 rising, the buckle 132 must be firmly supported with the right hand. With the buckle 132 supported in this manner, the free end 134 of the belt 131 is guided in a direction indicated by an arrow S through the insertion slit A with the left hand. Then the buckle 132 is further swung in a direction indicated by an arrow X while the free end 134 having been guided through the insertion slit A is maintained under an appropriate tensity until the buckle 132 is collapsed onto the peripheral surface 105a as indicated by imaginary lines in FIG. 8. In this way, the operation of immobilizing the air cylinder 105 by the cylinder band 102 is completed.
In the course of immobilizing the air cylinder 105 using the cylinder band 102 disclosed in REFERENCE, the belt 131 under a high tensity might move the buckle 132 in the direction opposite to the arrow X, i.e., move back to its position indicated by solid lines and the belt 131 might be slackened in the course of guiding the free end 134 of the belt 131 through the insertion slit A so far as the diver continues to support the buckle 132 with the left hand in order to keep the buckle 132 rising. In this manner, the diver is required to use his or her both hands continuously until the operation of immobilizing the air cylinder is substantially completed.